Home defense - not really. I could think of many other calibers I would rather shoot a bad guy with than a 22.

Target shooting - once again, not really. Luger sights generally are very hard to use. The barrel is very light, in relation to the rest of the gun, so it doesn't hang very well while you are trying to put bullet after bullet through the same hole in the paper. The trigger on a luger is too sloppy for precision target work, and there is not much that can be done to it to make it crisper. The trigger observation applies to a "real" luger. I don't know whether the Stoeger 22 uses the same trigger mechanism, or whether it just is, "externally", a luger. But the sights and the barrel comments apply, either way.

Plinking - absolutly. The luger is a very natural pointing pistol. Easy to bounce coke cans around with, or bust vanilla wafers. And 22 is cheap enough that you can afford to play with it a lot.

Mosin, as a pistol for target shooting or plinking, it is an excellent choice. The .22 LR round can't be beaten for those purposes and for just plain fun shooting. For home defense, it would not be, by any means, the one I would choose. While the .22 can indeed be deadly--let there be no mistake on that--it lacks sufficient terminal energy to be a reliable man stopper. Indeed, there is an old saying about the .22 and the .25 in that regard: "It's just big enough to make a little man sick and a big man mad."